Tension-pulley.



J. GARTZWEILER. TENSION PULLEI. AYPLIOATION TILED JULY 15, 1908.

932, 1 17 Patented Aug, 24, 1909.

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WkeM e [12 $07250?- ANDREW. a GRAHAM ca. mom-umonnwusns. wAsmNuraN v cUNITED STATES PATENT OFFICE.

JOHANN GARTZWEILER, 0F LEIPZIG-GOHLIS, GERMANY.

TENSION-PULLEY T 0 all whom it may concern:

Be it known that I, J OI-IANN GARTZWEILER, a subject of the GermanEmperor, and resident of Leipzig-Gohlis, Germany, have invented certainnew and useful Improvements in Tension-Pulleys, of which the followingis a specification.

This invention has reference to a belt, rope or chain drive and moreespecially to a drive of this kind provided with a tension pulley, theobject of the invention being to provide a drive of this kind whereinmeans are provided for controlling the pressure exerted by the saidtension pulley or idler on the flexible driving member. As a matter offact, experience has shown that when the speed of the drive increases,the friction between the belt, rope or chain and the pulley or wheel isconsiderably increased too and that consequently the circumferentialforce which can be transmitted is also increased. On the other hand innearly all the industrial engines to be driven the circumferential forcenecessary for the starting operation, is by reason of the accelerationforces and the increased bearing frictions to be overcome, considerablygreater than the circumferential force necessary for the working itself.It follows therefrom that the belts used in the usual belt drives mustbe tensioned with a much greater force than would be necessary for theworking proper, whereby the efliciency of the belt drive is considerablyreduced.

The device shown in the annexed drawing has for its object to reduce thetension of the tractional member down to the necessary amount.

In this drawing :Figure 1 is a view, partly in elevation, partly insection, of a tension pulley provided with the tension controllingdevice constructed according to the principles of the present invention,while Fig. 2 is a diagrammatical view of the belt drive.

The device is constructed and works in the following manner.

The crank levers a (Fig. 1) carry at one of their ends the masses 1)adapted to participate in the rotation and which during the rotation ofthe pulley are thrown outward by the centrifugal force. The other branchof the crank levers a pushes thereby the disk 0 outward in the directionof the axis of the pulley shaft. The disk 0 arranged at the opposite endof the said pulley is moved in a Specification of Letters Patent.

Application filed July 15, 1908.

Serial No. 443,724.

similar manner by a pair of inversely arranged crank levers which areangularly disposed with reference to the first named pair of cranklevers a. The separation of the disks 0 and 0 also causes the ends ofthe crank levers d to be separated from each other. As the crank leversare rotatably supported at e, the free branches thereof are moved upwardduring the said separation whereby the raising of the roller and consequently the reduction of the tension of the tractional member areobtained.

The crank levers d are pressed down in a yielding manner by means ofcoiled springs f arranged on rods 9 which are hingedly connected at hwith the said crank levers d.

Having now fully described my said invention, what I claim and desire tosecure by Letters Patent, is:

1. In a flexible drive the combination with the flexible driving member,of a tension pulley, suspending means therefor, a plurality of cranklevers hingedly connected with the hub of said tension pulley andprovided with weighted ends adapted to be thrown outwardly by the actionof the centrifugal force, the other ends of the said crank levers beingadapted to act upon the suspending means of the said pulley so as tomove the latter away from the flexible driving member when the speedthereof is increased, substantially as and for the purpose set forth.

2. In a flexible drive the combination with a flexible driving member, aframework, a tension pulley, a shaft therefor, a bearing for each end ofsaid shaft, a crank lever for each end of said shaft having one of itsends pivotally connected with the said framework above the said tensionpulley and the other end pivotally connected with one of said bearings,a disk arranged in each end of said tension pulley and adapted to slideon the shaft of said pulley and to move the said bearing outwardly, aplurality of crank levers pivotally connected with the hub of saidtension pulley and carrying at one end centrifugal weights, their otherends forcing said disks axially outwardly when the said centrifugalweights are thrown outwardly radially by the action of the centrifugalforce, substantially as and for the purpose set forth.

3. In combination, a flexible transmission member, pulleys about whichsaid member is trained, a hollow inclosed tension pulley idly PatentedAug. 24:, 1909.

- varying the tensioning action thereof.

5. In combination, a flexible transmission member, pulleys about whichsaid member is trained, a hollow inclosed tension pulley idly engagingsaid member between said pulleys, yieldingly actuated supporting armspermitting movement of said pulley to vary the tension on saidtransmission member, and centriiugally acting means located Whollywithin said pulley and acting on said arms for varying the tensioningaction of said pulley upon said member.

In testimony whereof I have hereunto set my hand in presence of twowitnesses.

JOHANN GARTZWEILER. Witnesses:

RUDOLPH FRIoKE, CARL STREGLER.

